$this->addElement(
                          'DateTextBox',
                          'sfl',
                          array(
                                'required'   => false,
                                'filters'    => array(),
                                'validators' => array(),
                                'label'      => 'SFL:',
                                'selector'   => 'date',
                                'default'    => ''
                               )
                         );

        if ($this->getRequest()->isPost() && $form->isValid($this->getRequest()->getPost())){
            //$values = $form->getValues();
            $values = $this->getRequest()->getPost();
            echo 'sucess';

        }


/**
The html rendered by the above element looks like this

<input class="dijitReset dijitInputInner" dojoattachpoint="textbox,focusNode" autocomplete="off" type="text" aria-valuenow="null" aria-invalid="true" id="sfl" tabindex="0" aria-required="true" value="">

Note the aria-required="true"
**/